Composition of waterproof agent and process for manufacture of waterproof cloth using the same



United States Patent COMPOSITION OF WATERPROOF AGENT AND PROCESS FOR MANUFACTURE OF WATER- PROOF CLOTH USING THE SAME Nobuyuki Adachi, Annaka-shi, Japan, assignor to The Shin-etsu Chemical Industry Company, Limited, Tokyo, Japan, a corporation of Japan N0 Drawing. Filed Dec. 1, 1964, Ser. No. 415,152

Claims priority, application Japan, Dec. 7, 1963, 38/65,838; June 13, 1964, 39/333361 6 Claims. (Cl. 117-161) ABSTRACT OF THE DISCLOSURE A waterproofing composition comprising (1) a hydroxyl terminated polydimethylsiloxane, (2) a methyl hydrogen polysiloxane, (3) an aminoalkyloxysilane, (4) a tetravalent organotin compound, and (5) an organic solvent. The invention also includes the combination of said waterproofing composition and an organic resin. The invention further includes cloth which is waterproofed with the aforesaid compositions and the processes for preparing said waterproofed cloth.

This invention relates to a composition of matter for the manufacture of a waterproof cloth and a process for the manufacture of a waterproof cloth.

A number of processes have been already proposed for the manufacture of a waterproof cloth and many products have been already manufactured according to the said processes. However, those processes belong to any of the following two types. That is, one of the said processes is to treat a cloth by immersing it in an emulsion or solution of an aluminum or zirconium soap, or a water repellent material such as paraffine, silicone, pyridine and others, or by spraying the said emulsion or solution on to the cloth, and then carrying out drying and heat treatment. In the said process, water-repellent film is formed around each individual fiber composing the cloth, and thus the excellent water-repellent property can be imparted to the cloth, but in this case the clearance between fibers, namely, the mesh of cloth is not clogged so that the hydraulic resistance is very poor. The waterrepellent property is also reduced due to the friction and crumpling during the washing on application. Such is a disadvantage of the said process. Conventional silicone water-repellents, for example, the repellents according to US. Patents 2,588,366, and 2,612,482 and the like, are entirely based on the said process. In the case of the process, there has been a disadvantage to select the cloth having dense texture for the high hydraulic resistance.

Another process is to coat the surface of a cloth with a high polymer resin solution of a synthetic rubber, polyvinyl chloride, polyacrylic acid, polyurethane and the like and carrying out vulcanization, if necessary, after the evaporation of the solvent and form a waterproof film on the surface of the cloth. In the said process, the mesh of cloth is clogged with the said high polymer film, so that the waterproof property of cloth can be remarkably improved. However, as these resins have no water-repellent property, the waterproof cloth prepared according to the said process has such a disadvantage as incompleteness of water-repellency. In order to eliminate such a disadvantage, it is necessary to carry out the water-repelling treatment of the said cloth further with the above mentioned paraffine or silicone water-repellent. Therefore, the said process requires two-step treatment.

The object of the present invention is to eliminate such disadvantages as conventional processes have and to provide a silicone composition for readily manufacturing a waterproof cloth excellent in both water-repellent prop- 3,418,162 Patented Dec. 24, 1968 erty and waterproof property and a process for the manufacture of waterproof cloth using the said composition. That is the present invention relates to a composition consisting of (1) a linear dimethyl polysiloxane having a hydroxyl group combined with a terminal silicon atom, (2) a methyl hydrogen polysiloxane having the formula:

c113) nHmsio where n=l.0-1.5, m=0.75-1.25, and m+n=2.0-2.25, (3) amino alkyl alkoxysilane having the formula:

filla ZRSi( )a-.

where R represents an alkyl group having less than 4 carbon atoms, R is an alkylene group having more than 3 carbon atoms, Z is an amino group or polyamino alkyl group combined to R through a carbon-nitrogen bond, R" is an alkyl group of less than 4 carbon atoms or phenyl group, and a represents 0 or 1, (4) an organotin compound having the formula:

Sn R. R

where R R R and R represent alkyl or acyl groups of less than 18 carbon atoms or phenyl groups, and (5) organic solvent, and to a process for the manufacture of waterproof cloth, which is characterized by coating the surface of the cloth with the said composition and carrying out heat treatment thereof after the evaporation of solvent.

Further explanation will be hereunder made in detail. The composition of the present invention is prepared by simply mixing the said constituents. For example, it is prepared by blending (1) from 5 to 50 parts by weight of linear polysiloxane having hydroxyl group combined with silicon at the terminal of molecule, (2) from 0.3 to 30 parts by weight of methyl hydrogen polysiloxane, (3) from 0.02 to 5 parts by weight of amino alkyl alkoxysilane, (4) from 0.1 to 5 parts by weight of organotin compound, and (5) from 35 to parts of organic solvent. However, if methyl hydrogen polysiloxane is used in an excess proportion to the linear dimethyl polysiloxane having hydroxyl group combined with silicon at the terminal of molecule in this case, the viscosity of the said solution decreases and thus it becomes hard to apply the coating on the cloth. On the other hand, if the amount of methyl hydrogen polysiloxane is too small, a weak film is brought about at the heat treatment of the coated surface. Therefore, it is desirable that the ratio of dimethylpolysiloxane to methylhydrogenpolysiloxane is 5:1-20:1, preferably about 10:1. Addition of pigment or coloring agent such as titanium oxide, aluminum oxide, calcium carbonate, silica and the like may be carried out at discretion if necessary.

According to the method of the present invention, the treatment of cloth is generally carried out by coating the cloth with the said solution by means of knife coater or roller coater, where the viscosity of the said solution is desirable in a range of 1,000 to 100,000 cps. for the most cases and 5,000 to 20,000 cps. for the preferable case in view of operational efficiency, and the concentration of resin is desirable in a range of from 5 to 50%, preferably from 10 to 30%. The viscosity and concentration can be adjusted by the amount of organic solvent to be added according to the processing apparatus, processing speed, kind of cloth, the amount of coating and the like.

There is no special restriction to the cloth to be treated according to the method of the present invention. In other words, nylon, Dacron (polyester), polypropylene fiber, cellulose acetate, bemberg, rayon, cotton, and

3 other can be applied. However, a good effect can be generally obtained in case of cloth having a texture consisting of long filament fibers with less raised nap. The amount of resin to be applied on these cloth is desirable at more than 3 grams per m of cloth for the ordinary case, and 5 to 30 grams for a preferable case. In carrying out the said processing, such a method as heating is carried out at from 60 to 100 C. for from 30 seconds to 5 minutes after the coating with the said treating solution to distill off the solvent and then further heating is carried out at from 120 to 180 C. for from seconds to 5 minutes is employed, whereby the resin components is subjected to polymerization and condensation, resulting in hardening. In this method, the objective waterproof cloth can be readily obtained. The waterproof cloth thus obtained has a coating of silicone resin having a special structure on the surface thereof and has a variety of excellent effects as follows: Namely, the waterproof cloth prepared in the conventional, well-known process, for example, the cloth coated with acrylic resin or urethane resin, lacks in the water-repellent and lightresistant properties. Further, these resins are readily attached by the solvent, and thus there is such a drawback as the said waterproof effect is readily lost through dry cleaning. The cloth treated with vinyl chloride and urethane resin is particularly inferior in the lightresistant property. For example, through the sun light irradation in a short period of time, the color of cloth is readily changed into yellow and the cloth becomes deteriorated. The cloth treated with the conventional waterrepellent agent of paraffin series or silicone lacks in the waterproof property, moreover there is such as drawback as the water-repellent film drops off through the repeated washing. On the other hand, in the cloth obtained in the present invention, the resin components extend to the fine texture of cloth owing to lower surface tension property of silicone resin used in the said treatment, and are subjected to hardening through the succeeding heat treatment, whereby the excellent waterrepellent property as Well as the water-proof property characteristic of the silicone resin can be imparted on the treated surface. Because of the lower surface tension property of silicone resin, a part of said resin composition treated on the cloth is easy to diffuse from its coated side to the back side.

As a result, both sides of such cloths treated as tafieta or twill become to have less wettable and rapiddrying property owing to its good water repellency. Moreover this coating film is not attached with the solvent, such as trichloroethylene, perchloroethylene, mineral turpentine, and therefore the waterproof property is not decreased through the repeated dry cleaning and no change nor deterioration is brought about at all through the sun light irradiation for a long period of time. Such effects can be imparted to the cloth coated according to the present invention. The film of silicone resin formed through coating according to the method of the present invention can endure hard friction, repeated crumpling and flexing sufiiciently, and thus the cloth obtained according to the method of the present invention is imparted with such a property as durable in severe service. Further, the film obtained in the present invention has a good stretching and flexible property and thus the strain from the outside is widely dispersed. So, in the cloth thus obtained, the tearing strength is remarkably improved, as compared with that of the original cloth, often reaching up to 200%. This fact is industrially important to the cellulose acetate and bemberg cloth which has poor tearing strength.

The mechanism of imparting the waterproof and waterrepellent property to the cloth treated according to the method of the present invention is explained as follows: Methyl hydrogen polysiloxane used in the present inven tion acts as the bridging agent to develop polysiloxane having the terminal hydroxyl group into a higher polymer substance, and further the said aminoalkyl alkoxysilane acts as the controlling agent for the said reaction rate, whereby the soft and powerful waterproof film is assumed to be formed on the objective cloth together with the presence of organotin compound as the reaction catalyst. However, it is not always definitely clear in this case what action aminoalkyl alkoxysilane actually performs. In case that aminoalkyl alkoxysilane is not added, it is observed that the viscosity of the solution rapidly increases and thereby the processing operation becomes very diflicult, and further the film thus obtained becomes very weak. The waterproof cloth thus obtained tends to be cracked readily through the friction and washing and the waterproof and water-repellent property decreases. Further, in case that aminoalkyl alkoxysilane is provided on the fiber in advance and the composition of matter having the above-mentioned blending ratio free of aminoalkyl alkoxysilane is coated thereon, only such waterproof cloth not good in the friction resistance and washing resistance is obtained. In view of the above facts, it seems that aminoalkyl alkoxysilane controls the reaction rate and takes an important role in the formation of soft and powerful film on the fiber. The wide change of solution viscosity is unpreferable in industrial application, therefore the addition of aminoalkylalkoxysilane is necessary.

Linear polysiloxane having hydroxyl group combined with silicon at the terminal of molecule, used in the present invention has the following general formula:

is polymerized with caustic potassium as the catalyst, and the polymer having a low viscosity can be obtained by heating the said high viscosity polymer with water to more than about C.

Further, methyl hydrogen polysiloxane is linear or cyclic polymer having the following general formula as the constitutional unit:

where n=1.0-1.5, m=0.75-1.25, and m+n=2.0-2.5. For example, such linear polysiloxane having the following formula as prepared by the simultaneous hydrolysis of trimethyl monochlorosilane and methyl dichlorosilane:

where n is the positive integer.

Aminoalkyl alkoxysilane, another material used in the method of the present invention, is represented by the general formula,

where R is alkyl group having less than 4 carbon atoms, R alkylene group having more than 3 carbon atoms, R" alkyl group having less than 4 carbon atoms or phenyl group, a represents 0 or 1, and Z amino group or polyaminoalkyl group combined to R through carbon-nitrogen bond, and is, for example, represented by the following molecules:

CH3 vention will be made hereunder with reference to ex- IIzNCHzCHzCHzKOCzHsM amples. EXAMPLE 1 CsHs 5 (1) Preparation of raw material mNcH cmomsuooeHe): Octamethyl cyclotetrasiloxane, [(CH SiO] was 2 2 2 2 2 2 5)3 heated at 150 c. for 3 hours with 0.001% by weight HzNCHZCHzNHCHZCHZCHZSi(OC2H5)3 of caustic soda in respect to the weight of the former to prepare dimethyl polysiloxane having hydroxyl group E at the terminal and a viscosity of 8,000,000 cps., and

H2NCHZCH2NHCH2CHCH2SKOC2H5)3 95 parts of monomethyl dichlorosilane, CH HSiC1 and H 00 H 5 parts of trimethyl chlorosilane, (CH SiCl underwent HZNCHZCHZNHCH2CH2NHCH2CH2C 2 1( 2 5)3 simultaneous hydrolysis at 25 C. to prepare methyl H N(CH NHCH CH CH Si(OC H hydrogen polysiloxane having a viscosity of 17 cps.

h On the other hand, trichlorosilane and alkyl chloride SOme of The 531d molecules can be Obtamed by t e underwent reduction in the presence of H PtCl catalyst methods indicated in pafent 233L754 when? h and were boiled to distill off 'y-chloropropyl trichlorohalogelloalkyl alkOXY sllafle l f ig s lg i t g gg silane having a boiling point of 183 C., which was then 3211 13 r2 f l l sh f r git i i ifizgeg w-ifl-l p ofyam sub ected 1to reactronfatlroom tefrnperatur;l 1with metlllanol 9 in a mo ar ratio 0 :3 to orm 'y-C oropropy tricarried out. The am 0f am 1n0a1kY1 i ii i i methoxysilane. Then, the resulting 'y-chloropropyl tri- Preferably afided l respect 0 e 0 a methoxysllane was added into a stream of excess ethylene i iie rgiii fin g iiig fi well known in the treatment of i g e g froml the top of g distilgng (5011mm an coo e e upper ayer separate rom t e said twosilrcone series water-repellent can be used. For example, y layer Solution was subjected to the distillation, whereby dibutyl tin diacetate, dibutyl tin dilaurate, dibutyl tin pure dioctoate, trimethyltin acetate, dioctyltin diacetate,

dibutyltin acetate. For the solvent used in the present in- 2 2 2 2 2 2 IQB vention, there is not a special restriction so long as the which boiling point is 5 C (15 mm Hg column) said solvent can dissolve the said respective constituent, was obtained,

but is inert thereto. Generally, trichloroethylene, per- 0 chloroethylene, benzene, toluene, mineral spirit and the like are in practice. The substances obtained in the foregoing were com- It is preferable that the composition of the present inbined and blended as in Table 1, and dissolved in trivention is used together with the well-known water-proofchloroethylene to obtain a viscosity of about 9,000 cps.

ing agent, for example, a resin component selected from suitable for knife coating and added finally with dibutyl (2) Preparation of treating solution ester of acrylic acid, urethane resin, and chlorosultin dilaurate.

TABLE 1 Dimethyl Methyl hydrogen H2NCH2CH2HNCHg Trichloro- Dibutyl tin Sample Number siloxane polysiloxane CHaCHqSKOMeh ethylene dilaurate (parts by weight) (parts by weight) (parts by weight) (parts by weight) (parts by weight) Runs 1 18 2 3 79.8 07 2 Comparison 4 18 2 79.8 0. 2

phonated polyethylene, in addition to the above-men- (3) Processing of cloth tioned constituents, whereby expensive silicone constituent can be effectively saved. In the present invention, the well-known resins used together with the abovementioned composition are acrylic ester resin, urethane resin and chlorosulphonated polyethylene. Copolymer of acrylic acid resin with metacrylic ester, acrylonitrile, styrene, butadiene and the like may be used if necessary, but in the most cases, copolymer mainly of butylacrylate with acrylonitrile which has the best hand and good adhesion with the fiber is used. lior urethane resin, those of test samples were prepared Then, the Water repenent prepared from polyester especially having or 3 hyproperty and water-proof property were measured, of Y groups at the termlnal and multlfunctlonal 0 these samples, for the finished cloth (prior to the dry isocyanate are preferable. For chlorosulfonated polyethylcleaning) the cloth Subjected to the shaking in trichlene The said solutions were coated respectively on the nylon tafleta cloth with knife coater so as to coat the cloth evenly at 10 grams per m with the said treating resin, and then, heat treatment was carried out at 90 C. for 3 minutes and further at 140 C. for 3 minutes. For comparison, the cloth coated with acryl resin (Sample Number 6) and the cloth further treated with silicon series water repellent (market-available emulsion type) (Sample Number 7) were prepared. Namely, seven kinds 111036 f y, market-available Ones hiiving at 25 C. for 30 minutes (after the dry cleaning) and the molecular wei ht of from 10,000 to 100,0000 are in praccloth subjected to crumpling which took place 500 times trce. under the pressure of 1 kg. using a Scott type folding and Further explanation of the method of the present mabrading tester, and the result thereof is shown in Table 2.

TABLE 2 Finished cloth Cloth after dry cleaning Cloth after erurnpling resistance test Sample Number Water repellence Water proot'ness Water repellence Water proofness Water proofness Water prootness Example 1 100 1, 020 100 450 400 2 1, 050 100 1, 010 100 970 3 100 910 100 890 100 890 Comparison 4 100 1, 030 70 210 60 5 0 60 0 20 0 20 6 50 250 30 30 50 7 100 300 80 7 80 EXAMPLE 2 The above-mentioned linear dimethyl polysiloxane having hydroxyl group at the terminal of molecule was dissolved in solvent in advance, and other constituents were 8 waterproof cloth thus obtained and those washed under the condition of AATCC No. 2, the water proofness and the water repellence of both sides of cloth were measured, and the results as shown in Table was obtained. The

thereto added. In this wa the test solutions havin the 5 method for the measurement was in accordance with u I y a composition as shown in Table 3 were prepared and the AATCC 22-1952.

TABLE 5 S l N b Cloth before washing Cloth after washing amp e um er Hydraulic Water repellency Water repellency Hydraulic Water repellency Water repellency resistance, mm. of coated side of back side resistance, mm. of coated side of back side 23 a 2 25 0 0 0 0 1, 000 100 100 250 so 60 1, 000 100 100 1, 000 100 100 g 0 8 20 0 0 o 20 0 0 1, 000 100 100 270 70 e0 1, 000 100 100 1, 000 100 100 400 90 90 85 e0 0 change in viscosity of these solutions was determined at EXAMPLE 3 u ts h wn in F 95;; fmperature C) The res l are s o The above-mentioned linear dimethylpolysiloxane hav- 25 mg hydroxyl group at the terminal of molecule and methyl TABLE 3 hydrogen polysiloxane were blended with Dimethyl Methyl Amino Organo Trichlo- Sample polysiloxhydrogen alkyl alkoxymetallic roethyl- CH3 Number lzine (pegs poly(sil0)tlsglane (pigs (:(omgotgnd eneb y weig ane par s y weig par 5 y par s y by weight) weight) Weight) HflNOHgCHaGHzSKO 02135),

5 218 8. 2 ii-6 73-; and dibutyltin diacetate as shown in Table 6, and the 10 1 "553"" 1 solutions thus obtained were coated on the Dacron (poly- 11 18.0 2- 0 1 0.2 2 0- 6 ester fiber) tafetta cloth so that the resin may be adhered 12 20.0 m2 Q7 at 8 grams/m and then heat treatment was carried out g g 3 0. gg-g at 90 C. for 3 minutes and 120 C. for 5 minutes, where- 15 I: 1 ""a'd' 4 3y the waterproof cloth was Iobtained. For these cloths, e water repe ence and ydraulic resistance were 1 1. 2.0 0.2 0.7 79.1

6 8 0 measured before and after the washing in a way s1m1lar to 1 HzN(CH2)3Si(OC2H5). zDibutymn dioctoate 40 that m Example 2, and the result shown in Table 7 was a mmonommonmsno0H,). Obtamed- 4 Dibutyl tin dilaurate. 5 HZNCHZCHZNH.

TABLE 4 TABLE 6 Sample After Alter After After Number Prepgatmn' 1 5 24 Sample m gt hyl h g iiigein S i C 1 1 Perchloro- N0. siloxane po1y- I etate ethylene 9, 200 9, 300 9, 2 9, 88 5110mm CH3 8,500 8,500 8, s s, 700 23, 500 125,000 1g g g- 3 6 1 s, 400 8,500 3, 500 8,600 0 6 1 9, 300 9, 300 9, 500 9, 650 0 -g 3 6 1 8,600 8,600 as, 00 8,700 3 6 1 2 1 18.0 2.0 0.05 0.6 79.35 35000 O O is 0 2 0 0 1 0 e 9 3,400 3,400 8,500 8,500 1 0 7 8,950 15, 300 36. 800 3-8 0 g g l Complete hardening. 3 Almost hardened. 0 0 2 2 6 TABLE 7 s I N b Before washing After washing ampe um er Hydraulic Water repellency Water repellency Hydraulic Water repellency Water repelltncy resistance, mm. of coated slde of back side resistance, mm. of coated side of back side as .23 .9 s9 70 90 70 1, 000 100 100 1, 000 100 100 1, 000 100 100 1, 000 100 100 1, 000 100 100 720 90 80 1, 000 100 100 1,000 100 e20 s0 70 270 60 50 1, 000 100 950 100 90 1, 000 100 100 1,000 100 100 Then, the test solutions just right after the preparation EXAMPLE 4 were evenly coated on the Dacron taffeta cloth with the doctor knife so that 30 g. of the test solution, namely 6 g. of the resin component, may be adhered on the cloth per 1 m? of cloth, and the coated cloth was immediately heated to 90 C. for 3 minutes to evaporate the solvent Coating was made, in varied amount of resin to be adhered, to the nylon taffeta and polypropylene fiber canvas sheet using the solution of Sample Number 11 in Example 2, and heat treatment was carried out at 90 C. for 3 and further heated to 140 C. for 3 minutes. For the 75 minutes and at C. for5 minutes, whereby the waterproof cloth was obtained. The water repellence and hydraulic resistance of cloth thus obtained were measured, and the result as shown in Table 8 was obtained.

TABLE 8 Polypropylene canvas Sample Amount of resin Number adhered, g./m. Hydraulic Water repelleney Water repellency Hydraulic Water repellency Water repellency resistance, mm. of coated side back side resistance, mm. of coated side of back side EXAMPLE 5 of methyl hydrogen polysiloxane represented by the gen- Silicone having a composition of Sample Number in Example 2 and market-available acrylic acid resin (copolymer of butyl acryl-ate and acrylonitrile) were blended in various proportion and were dissolved in trichloroethylene so that the total resin content may amount to 15%. Then, the solution was coated on the acetate tafieta so that the resin may be adhered at 5 grams/m2 and the heat treatment was carried out at 90 C. for 3 minutes and iurther at 140 C. for 5 minutes. For comparison, the cloth coated with silicone alone, the cloth coated with acrylic acid resin alone, the cloth subjected to the waterrepellent treatment with market-available emulsion-type silicone water repellent after the coating of acrylic acid resin, and further the cloth subjected to the water-repellent treatment only with the said emulsion-type, silicone water-repellent were subjected to the said treatment, likewise. In the processing with the said emulsion-type, silicone water-repellent, dilution was made to the solution with water so that the silicone content may reach 4%, and the cloth to be treated was immersed in the solution. After the squeezing of the cloth with mangle, heat treatment was carried out to the treated cloth at 90 C. for 5 [minutes and further at 160 C. for 5 minutes.

The waterproof cloth thus obtained was subjected to dry cleaning in perchloroethylene for 30 minutes and change of the water-repellent property and the hydraulic resistance thereof was observed. The result thus obtained is shown in Table 9. The tearing strength and the flex abrasion resistance of the cloth prior to the dry cleaning were determined according to CCC-T-19lb and the reeral formula,

where n=l.0-l.5, m=0.751.25 and n+m=2.02.25, (3) from 0.02 to 5 parts by weight of aminoalkylalkoxysilane represented by the general formula,

wherein R is an alkyl group having less than 4 carbon atoms, R is an alkylene group having more than 3 carbon atoms, R" is selected from the group consisting of alkyl groups having less than 4 carbon atoms and phenyl groups, Z is selected from the group consisting of amino and polyaminoalkyl groups bonded to R through a carbon-nitrogen bond, and a represents zero to l, (4) from 0.1 to 5 parts by weight of organotin compound represented by the general formula,

where R R R and R are each selected from the group consisting of alkyl and acyl groups containing less than 18 carbon atoms, and phenyl groups, and (5) from 35 to 95 parts by weight of organic solvent.

2. A process for the manufacture of waterproof cloth, characterized by applying a solvent containing composition of a waterproofing agent to a cloth, evaporating said solvent and then heat-treating said cloth, said 501- sult thereof is shown inTable 10. vent containing composition comprising (llfrom 5 to TABLE 9 Before dry cleaning After dry cleaning Sample Silicone Acrylic ester Number resin resin Hydraulic Water Water Hydraulic Water Water resistance, repellency repellency resistance, repellency repellency mm. of coated side of back side mm. of coated side of back side 100 820 100 100 860 100 100 20 790 100 100 770 100 100 60 40 750 100 100 490 90 40 60 700 90 330 90 80 20 80 520 80 60 60 50 100 460 50 0 45 0 0 Silicone water repellent treat- 610 90 100 80 80 ment after acrylic acid resin coating. 38 Only silicone water repellent 190 100 100 110 80 80 treatment TABLE 10 parts by weight of a hydroxyl terminated polydimethyl- Tearing Strength Flex Abrasion siloxane having a viscosity less than 10,000 cps. at 25 sample gimme Acrylic (pounds) Resistance 0, (2) from 0.3 to 30 parts by weight of methyl hydro- Number resm aci ci e ter yc gen polysiloxane represented by the general formula,

, 65 Fill W arp F111 (C H3) nHmSlO 9.7 112 67 where n=1.01.5, m=0.75l.25 and n+m=2.0-2.25, 1 g 32 g (3) from 0.02 to 5 parts by weight of aminoalkylalkoxyg8 23 g 7 O silane represented by the general formula,

What I claim is: 1. A waterproofing composition which comprises (1) wherein R is an alkyl group having less than 4 carbon atoms, R is an alkylene group having more than 3 carbon atoms, R" is selected from the group consisting of alkyl groups having less than 4 carbon atoms and phenyl groups, Z is selected from the group consisting of amino and polyaminoalkyl groups bonded to R' through a carbon-nitrogen bond, and a represents to 1, (4) from 0.1 to parts by weight of organotin compound represented by the general formula,

wherein R R R and R are each selected from the group consisting of alkyl and acyl groups containing less than 18 carbon atoms and phenyl groups, and (5 from 35 to 95 parts by weight of organic solvent.

3. A process according to claim 2 wherein the composition of the waterproofing agent is applied to the cloth in a ratio of from 3 to 30 grams of resins of said agent per 1 square meter of the cloth, and the cloth is heated at a temperature of from 60 to 100 C. to evaporate said solvent, and then at a temperature of 120 to 180 C.

4. A composition having waterproofing characteristics, which comprises a mixture of (A) from 5 to 200 parts by weight of a resin composition consisting of (1) from 5 to 50 parts by weight of a hydroxyl terminated polydimethylsiloxane having a viscosity higher than 10,- 000 cps. at 25 C., (2) from 0.3 to 3 parts by weight of methyl hydrogen polysiloxane represented by the general formula,

(om) nrnnsio where n=1.01.5, m=0.751.25 and n+m =2.0-2.25, (3) from 0.02 to 5 parts by weight of aminoalkylalkoxysilane represented by the general formula,

wherein R R R and R are each selected from the group consisting of alkyl and acyl groups, containing less than 18 carbon atoms and phenyl groups, and (5) from 35 to 95 parts by weight of organic solvent, and (B) 100 parts by weight of at least one resin selected from the group consisting of acrylic acid ester resin, urethane resin, chlorosulphonated polyethylene.

5. A process for the manufacture of waterproof cloth,

where n:=1.01.5, m-=0.75-1.25 and n+m=2.02.25,

(3) from 0.02 to 5 parts by weight of aminoalkylalkox'ysilane represented by the general formula,

wherein R is an alkyl group having less than 4 carbon atoms, R is an alkylene group having more than 3 carbon atoms, R" is selected from the group consisting of alkyl groups having less than 4 carbon atoms and phenyl groups, Z is selected from the group consisting of an amino and polyaminoalkyl groups bonded to R thorugh a carbon-nitrogen bond, and a represents 0 to 1, (4) from 0.1 to 5 parts by Weight of organotin compound represented by the general formula where R R R and R are each selected from the group consisting of alkyl and acyl groups containing less than 18 carbon atoms, and phenyl groups, and (5) from 35 to parts by weight of organic solvent, and (B) parts by weight of at least one resin selected from the group consisting of acrylic acid ester resin, urethane resin, chlorosulphonated polyethylene.

6. A process according to claim 5, wherein the composition having waterproofing characteristics is applied to the cloth in a ratio of from 3 to 30 grams of resin of the composition per square meter of the cloth, and the cloth is heated at a temperaure of 60 to 100 C. to evaporate the solvent, and then at a temperature of to 180 C.

References Cited UNITED STATES PATENTS 2,985,544 5/1923 Monterey et al. 117-161 2,985,545 5/1923 Leavitt 117161 3,247,281 4/1966 Gagliardi 260-825 3,303,048 2/1967 Cooper et al. 117-1355 WILLIAM D. MARTIN, Primary Examiner.

THEODORE G. DAVIS, Assistant Examiner.

U.S. Cl. X.R. 

